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package cn.nju.zyy.basic.returnresult;

import java.util.ArrayList;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

/**
 *
 * @author yingyzhang
 */
class TaskWithResult implements Callable<String> {
    
    private int id;
    
    public TaskWithResult(int id) {
        this.id = id;
    }

    @Override
    public String call() throws Exception {
        return "result of TaskWithResult " + id;
    }
    
}

public class CallableDemo {
    
    public static void main(String[] args) {
        ExecutorService exec = Executors.newCachedThreadPool();
        ArrayList<Future<String>> results = new ArrayList<Future<String>>();
        for (int i = 0; i < 5; i++) {
            results.add(exec.submit(new TaskWithResult(i)));
        }
        for (Future<String> fs : results) {
            try {
                // get() blocks until completion;
                System.out.println(fs.get());
            } catch (InterruptedException ex) {
                System.out.println(ex);
                return;
            } catch (ExecutionException ex) {
                System.out.println(ex);
                return;
            } finally {
                exec.shutdown();
            }
        }
    }
}